Many conventional luminaries utilize incandescent or various types of fluorescent light sources. Limitations of many different types of luminaries stem from the need to address the dissipation of high amounts of heat, specifically from incandescent light sources. Known solutions include luminaire designs that are intended to be used in well ventilated setups, in which most of the outside surface of the luminaire—for example, a suspended spot light—is exposed to facilitate heat dissipation into the ambient environment via convection. Other luminaries, intended for applications where effective cooling via convection is limited, are often designed to dissipate waste heat via radiation or heat conduction. Such luminaries include so-called “recessed lights,” such as broad-angle flood lights and narrow-angle spot lights, designed for installation into insulated openings in walls or ceilings. Luminaries based on conventional light sources, while providing reasonably effective heat dissipation via radiation, suffer from lack of effective color and intensity control, low luminous efficacy, and a host of other disadvantages.
Recently, advances in the development and improvements of the luminous flux of light-emitting devices such as solid-state semiconductor and organic light-emitting diodes (LEDs) have made these devices suitable for use in general illumination applications, including architectural, entertainment, and roadway lighting. Functional advantages and benefits of LEDs include high energy conversion and optical efficiency, durability, lower operating costs, and many others, making LED-based light sources increasingly competitive with traditional light sources, such as incandescent, fluorescent, and high-intensity discharge lamps. Also, recent advances in LED technology and ever-increasing selection of LED wavelengths to choose from have provided efficient and robust white light and colour-changing LED light sources that enable a variety of lighting effects in many applications.
Many existing solid-state luminaries and luminaire designs, however, are complex, include large numbers of components and as a result their manufacturing can be resource- and cost-intensive. For example, maintaining a proper junction temperature is an important component to developing an efficient solid-state lighting system, as the LEDs perform with a higher efficacy when run at cooler temperatures. The use of active cooling via fans and other mechanical air moving systems, however, is typically discouraged in the general lighting industry primarily due to its inherent noise, cost and high maintenance needs. Thus, it is desirable to achieve air flow rates comparable to that of an actively cooled system without the noise, cost or moving parts, while minimizing the space requirements of the cooling system.
A number of solutions have been proposed, addressing the disposition of solid-state light sources and the configuration of cooling systems of luminaries in order to facilitate the heat dissipation and to mitigate undesirable effects caused by heating of solid-state light sources. Some examples include a number of products suitable for operation in recessed installations such as, a number of lighting products offered by various manufacturers that include 360 lm white LEDs manufactured by Cree Inc., or the LED Low-Profile Fixture Designs provided by the California Energy Commission in cooperation with the Architectural Energy Corporation and the Rensselaer Polytechnic Institute Lighting Research Center described at http://www.lrc.rpi.edu/programs/solidstate/.
Many known solutions, however, fail suggest a solid-state lighting device that provides good thermal management in combination with a modular configuration that allows adequate maintenance, replacement or repair of its components. There is, therefore, a need for a luminaire employing LED-based light sources that addresses a number of disadvantages of known solid-state lighting devices, particularly those associated with thermal management, light output, and ease of installation and maintenance.
This background information is provided to disclose information believed by the applicant to be of possible relevance to the present invention. No admission is necessarily intended, nor should be construed, that any of the preceding information constitutes prior art against the present invention.